<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<script>
document.write(ex());
</script>
body영역의 출력
<br/>
<input type="button" value="계산" onclick="alert(func())"><br/>
<script>
var x=10, y=20;
function func(){
	return x+y;
}
</script>
</body>
</html>